<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>盒子模型</title>
	<style>
		#div1{
			width: 700px;
			height: 700px;
			background-color: lightgreen;
			margin: 50px auto;
			padding: 50px ;
		} 
		#div2{
			width: 500px;
			height: 500px;
			background-color: lightblue;
			margin:80px;
			padding: 20px;
		}
	</style>
</head>
<body>
	<div id="div1">
		<div id="div2"></div>
	</div>
</body>
</html>